Peroxycarboxylic acids (i.e. peracids) are commercially-available antimicrobials, sanitizing agents and/or bleaching agents, which are generally sold in equilibrium solutions containing the corresponding carboxylic acid to the peroxycarboxylic acid, hydrogen peroxide and water. Antimicrobial compositions are used in a variety of automated processing and cleaning applications to reduce microbial or viral populations on hard or soft surfaces or in a body or stream of water. For example, antimicrobial compositions are used in various applications including kitchens, bathrooms, factories, hospitals and dental offices. Antimicrobial compositions are also useful in the cleaning or sanitizing of containers, processing facilities or equipment in the food service or food processing industries, such as cold or hot aseptic packaging. Antimicrobial compositions are also used in many other applications including but not limited to clean-in-place systems (CIP), clean-out-of-place systems (COP), washer-decontaminators, sterilizers, textile laundry machines, filtration systems, etc.
Regardless of the application, an antimicrobial or “use” composition is a composition containing a defined minimum concentration of one or more active components which exhibit desired antimicrobial properties. The concentration of active components in the use composition is chosen to achieve the requisite level of antimicrobial activity. In use compositions in which one or more peracids are the active component, the concentration of hydrogen peroxide tends to increase over time while the concentration of peracid decreases. However, in order to maintain the requisite level of antimicrobial activity, the amount of peracid in the use composition must be maintained at a defined minimum concentration. In addition, as the amount of hydrogen peroxide in the use composition increases, the use composition may exceed a defined maximum concentration of hydrogen peroxide in the solution.
To ensure the amount of peracid is maintained at or above some minimum concentration and to determine when the amount of hydrogen peroxide reaches or exceeds a maximum concentration, it is necessary to determine the concentration of peracid(s) and hydrogen peroxide in the use composition. In the past, to determine both the peracid concentration and the hydrogen peroxide concentration in a use composition has required multiple time consuming manual titrations, several different reagents and relatively large volumes of use composition. Moreover, past devices and methods for determining both peracid and hydrogen peroxide concentrations were effective over only a narrow range of concentrations.
Accordingly, it is an objective of the claimed invention to develop peracid compositions having various beneficial aspects, including compatibility for monitoring of peracid concentration by conductivity and/or optical sensors.
A further object of the invention is to provide a highly acidic, mixed peroxycarboxylic acid composition having such compatibility for concentration monitoring that is also low/no VOC, low odor, low foaming and stabilized under such highly acidic conditions (e.g. mineral acids in formulation).
Other objects, advantages and features of the present invention will become apparent from the following specification taken in conjunction with the accompanying drawings.